Dry mouth, which is characterized by decreased salivation, has a number of causes; the involvement of estrogen has been suggested as symptoms typically develop in middle-aged females. However, there is a lack of consensus regarding the treatment of this condition. Because soy isoflavones share some properties in common with the hormone estrogen, Japanese researchers evaluated the effects of isoflavones on impaired salivary secretion in patients with dry mouth. Soy isoflavones (25 mg/day) were administered for two months to 15 study participants with an average age of about 70 years. The results showed a significant improvement based on the saliva flow rate and self-completed questionnaire, thus suggesting the usefulness of isoflavones in improving the symptoms of salivary gland hypofunction.
Ryo K, Takahashi A, Tamaki Y, et al. Therapeutic effects of isoflavones on impaired salivary secretion. J Clin Biochem Nutr. 55,168-173 (2014).